quick differential question
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quick differential question
where is the id tag located on the differential?, im curious to see what gear ratio i have, i want to improve my fuel milage if possible, diesel prices are insane here in canada, thanks in advance- its a 1994 f250 turbo, overdrive trans
Post Fiend
Joined: Nov 2003
Posts: 21,285
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From: Nutter Fort, WV
The tag should be under one of the bolts on the rear axle cover.
The bolt head normally covers the first number.
So if it is an open differential you will probably see 10 or 55 as the first numbers on the bottom row.
If you see L10 or L55, then you have a limited slip.
The 10 would be a 4.10 ratio, the 55 would be a 3.55 ratio.
3.73 was not that common, but if you see 73 or L73, you know what you have.
Also there is a tag on the drivers door rear pillar.
What are the letter/number under axle?
The bolt head normally covers the first number.
So if it is an open differential you will probably see 10 or 55 as the first numbers on the bottom row.
If you see L10 or L55, then you have a limited slip.
The 10 would be a 4.10 ratio, the 55 would be a 3.55 ratio.
3.73 was not that common, but if you see 73 or L73, you know what you have.
Also there is a tag on the drivers door rear pillar.
What are the letter/number under axle?
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New User
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I can't read the tag anymore but it says axle 39 on the sticker on the inside of the drivers door if that helps
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Tuned
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If I have the 3.55 and the overdrive automatic what kind of rpm's should I get?, im getting 2300rpm at 110km/hr right now after a new rpm sensor and it seems high, what do you think and what could i do to bring em down?
Lead Driver
Joined: Nov 2003
Posts: 6,900
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From: Campbell River, B.C.
When cruising at a steady speed, like say 100 KPH, look at the tach and press the accelerator. Don't floor it, just accelerate moderately. The transmission should stay in top gear, and the tach should rigidly move with the speedometer needle indicating a locked TC.
If the tach drifts up in RPM (100-200 rpm) before a significant increase in speed, than the TC is not locked.
If the tach drifts up in RPM (100-200 rpm) before a significant increase in speed, than the TC is not locked.
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all tests check out good, i must have the 4.10 gears, the tires are 235/85/16, im going to pull the diff apart and count some gears, I can't see what else could cause these high rpms unless anyone has anymore ideas